Percutaneous Coronary Angioplasty is a therapeutic medical procedure used to increase blood flow through the coronary artery and can often be used as an alternative to coronary by-pass surgery. An elongated catheter having a deflated balloon at its distal end is guided through a patient's cardiovascular system to the coronary artery of the heart. The balloon is inflated to compress deposits that have accumulated along the inner walls of the coronary artery to widen the artery lumen and increase blood flow.
One prior art technique for positioning the balloon catheter uses an elongated guidewire that is inserted into the patient and routed through the cardiovascular system as guidewire progress is viewed on an x-ray imaging screen.
The path the guidewire follows as it is inserted is tortuous. The distal tip is flexible to avoid damaging inner walls of the blood vessels that the guidewire tip contacts along the tortuous path. The distal tip is often pre-bent to a desired configuration so that the guidewire can be inserted into the branching blood vessels along the path. When the tip is pre-bent the physician must be able to orient the tip so it can be pushed into these branching blood vessels.
Representative prior art patents that disclose flexible, elongated guidewires are U.S. Pat. Nos. 4,545,390 to Leary, 4,538,622 to Samson et al. and 3,906,938 to Fleischhacker. The Leary '390 patent discloses a narrow flexible guidewire having a distal portion that tapers and includes a flexible coiled spring at its distal end.